1. Field of the Invention
This invention relates to air-permeable waterproof products having fabric-like aesthetic properties and to methods for making such products.
2. Summary of the Prior Art
Heretofore, films have been prepared from synthetic resins or polymers such as polypropylene by various melt extrusion or casting methods. Such films have many desirable properties such as high strength, and resistance to heat, light, and various chemicals.
Moreover, for applications such as backings for medical dressings or bandages, films have been prepared which have the additional property of excluding liquids such as water while permitting the passage of air. Films possessing this additional property are described for example, in U.S. Pat. No. 3,426,754, which patent is assigned to the assignee of the present invention.
While the above-described air-permeable water proof films of the prior art are useful, the search has continued for new products which in addition to being air-permeable and waterproof also have fabric-like aesthetic properties such as a good feel or hand. The latter is important from an aesthetic appeal standpoint for applications such as rainwear and shoe liners.